Thermoelectric Limitations of Graphene Nanodevices at Ultrahigh Current Densities

Evangeli, Charalambos and Swett, Jacob and Spiece, Jean and McCann, Edward and Fried, Jasper and Harzheim, Achim and Lupini, Andrew R. and Briggs, G. Andrew D. and Gehring, Pascal and Jesse, Stephen and Kolosov, Oleg V. and Mol, Jan A. and Dyck, Ondrej (2024) Thermoelectric Limitations of Graphene Nanodevices at Ultrahigh Current Densities. ACS Nano, 18 (17). pp. 11153-11164. ISSN 1936-0851

Abstract

Graphene is atomically thin, possesses excellent thermal conductivity, and is able to withstand high current densities, making it attractive for many nanoscale applications such as field-effect transistors, interconnects, and thermal management layers. Enabling integration of graphene into such devices requires nanostructuring, which can have a drastic impact on the self-heating properties, in particular at high current densities. Here, we use a combination of scanning thermal microscopy, finite element thermal analysis, and scanning transmission electron microscopy techniques to observe prototype graphene devices in operation and gain a deeper understanding of the role of geometry and interfaces during high current density operation. We find that Peltier effects significantly influence the operational limit due to local electrical and thermal interfacial effects, causing asymmetric temperature distribution in the device. Thus, our results indicate that a proper understanding and design of graphene devices must include consideration of the surrounding materials, interfaces, and geometry. Leveraging these aspects provides opportunities for engineered extreme operation devices.